Containers for viscous liquids such as detergents, shampoo, lotions, baby oil, etc., are well known and often have closures including a body portion (having a dispensing aperture) for positioning on or around the container head or neck (defining the container opening) such as via screw threads, and an integrally hinged cap portion for closing or sealing the dispensing aperture in the body portion. Frequently, the cap in its open position may have a tendency to move towards or block the dispensing aperture during the dispensing mode of the viscous liquid, thereby causing splashing of the dispensed liquid against the cap. Results include loss of liquid, splashing of the liquid onto clothes, floors and other undesirable places as well as generally causing messy conditions, as well as clogging of the dispensing aperture.
Many closures of this general type are provided with splash-proofing means for preventing the cap portion from blocking the dispensing aperture. It has been known from the patent literature over the years to equip the closure body portion with an integrally formed, generally vertically erect protrusion or cap guide to prevent movement of the cap towards the dispensing aperture during the dispensing of liquids held within the container. For example, U.S. Pat. No. 3,752,371 to Susuki et al; U.S. Pat. No. 3,853,250 to Alpern; U.S. Pat. No. 4,010,875 to Babiol; U.S. Pat. No. 4,158,902 to Chernack et al; U.S. Pat. No. 4,193,519 to Dubach et al; and U.S. Pat. No. 4,220,248 to Wilson et al all disclose closures including splash-proofing means for preventing the cap, when open, from moving towards the dispensing aperture or other discharge opening of the container. While all of these above-mentioned patents disclose closures of the splash-proof type, all suffer from at least one of a variety of deficiencies and for the most part these prior constructions have not been successful.
For example, the constructions of the aforementioned patents are unduly complex, being difficult to mold especially as a one-piece structure, and are accordingly expensive to manufacture. Injection molding, the process by which closures of this type are commonly formed, is very sensitive to processing economics. The molds used may have 48, 60, 72, 96, etc. cavities, and the molding must be carried out at high speed. If the cavities take excess space because of complexities of the shape of the cap, this means that the molds are more expensive to manufacture, slower to operate with increased cycle time, and more floor space is necessary, all of these factors increasing the cost of manufacture of the closure and the ultimate cost of the product. If the closure is particularly complex, it may require molding in two or more pieces with a consequent and extra assembly operation at the conclusion of molding. All these factors add to the cost, and all the structures of the aforementioned patents suffer from this problem.
Thus, the closure of Dubach U.S. Pat. No. 4,193,519 requires two levers or protrusions. In order to mold this device an undercut is required in one of the levers which increases the cost of the mold, limits the number of cavities available on the mold plate and lengthens the cycle time by having to actuate a slide to make the undercut. In addition, the closure itself has recesses which tend to fill with the viscous liquid product to be dispensed, providing a messy product. A similar problem of messiness exists with the product of the Wilson U.S. Pat. No. 4,220,248.
In Babiol U.S. Pat. No. 4,010,875 again two protrusions are used, increasing the cost to produce the mold, especially when large cavitation is required. Again an undercut is used on the lever on the pour half, increasing mold cost and lengthening cycle time. Again, projections and recesses in the resultant closure tend to provide a messy product in use.
The product of Susuki U.S. Pat. No. 3,752,371 requires manufacture using side core tools, here again increasing mold costs and cycle time. The product of Alpern U.S. Pat. No. 3,853,250 is a two-piece cap which must be assembled after molding, the assembly cost necessarily adding to the expense of the closure.
The closure of Cherneck U.S. Pat. No. 4,158,902 requires a split hinge which increases the likelihood of hinge breakage. Split hinges moreover have a space between the hinge sections which necessitates that the hinge sections are further out from the center line of the closure compared with a closure of similar size but having only a single hinge of the same length. A side thrust on the cap will have a greater torque action on the outside edge of the hinge because the force against the cap is multiplied by the distance of one hinge section from the other, whereas for a single hinge this distance is smaller and the resultant torque on the cap has less effect on the hinge. This cap also uses two levers, these actuating inside of the hinge sections; such a construction is very complex and requires very expensive molds.
Consequently, the art is in need of a reliable, inexpensive, splash-proof one-piece molded plastic dispensing closure particularly adapted for use with containers for dispensing viscous liquids.